your english is even poor as mine
a naiber,im from holland living near by your west border.And english is not american english,like the same as Hochdeutsch not austria deutsch is
that was a stetment
a answer of your question,if both work simutamesly,there shut be no problem, a headphone out is a line out[mostly 1,5 mv 50ohm]
it seams that hp 2 headphone connections[look at print one splitsed in two] for people who wil both to same music same pc different headphone,, why perhaps romantic keine einung.
but no more dreaming.. you can use omne for headphone other for line out